He passed away from cancer in 2019 just a few months after his role on season two of Cobra Kai. His Character Tommy passed away on Cobra Kai from cancer. I guess the original cobra kais getting together in the show one more time was their last hurrah with Rob, and their final goodbye to him. The scene was emotional and I was crying, if you haven't watched Cobra Kai on Netflix I recommend it, it does the original Karate Kid movies justice and pays a nice homage to Pat Morita, aka Mr. Miyagi.

Rob Garrison, the actor who played intense Tommy in "The Karate Kid" movies and appeared in the YouTube series "Cobra Kai," has died at age 59.
Garrison's manager Rick Henriques confirmed the news Friday with a statement:
"Rob was a great person and ambassador to 'The Karate Kid' legacy," the statement read. "He will be missed by me and everyone he encountered."
Tommy was a boisterous member of the villainous Cobra Kai dojo in 1984's “The Karate Kid,” which starred Ralph Macchio as the new kid in town who turns to martial arts in the face of bullying.
Tommy represented the full-on intensity of the maleficent Cobra Kai dojo, as seen in the infamous line to his bully teammate Johnny Lawrence (William Zabka) during the climatic final fight, “Get him a body bag! Yeah!”